Planar magnetron with moving magnet assembly

Abstract

The present invention provides a planar magnetron including a surface for mounting a planar substantially polygonal target (2) having a substantially central target area for sputtering onto a substrate. The magnetron comprises an array of magnets (4) defining a closed loop magnetic field for generating an elongated plasma race-track above the target (2). Means for establishing cyclical, relative, substantially translational movement between the race-track and the target support surface are provided, the substantially translational movement being substantially parallel to this surface and the trace of the substantially translational movement being a two-dimensional figure. The periphery of the race-track lies substantially within said substantially central target area throughout each cycle, the establishing means being adapted to provide a substantially uniform erosion of the target (2) at least within said substantially central target area.

Description

The present invention relates to an improved planar magnetron with a magnet assembly suitable for sputtering or reactive sputtering of materials from a cathode target onto a substrate as well as a method of operating the magnetron.TECHNICAL BACKGROUNDA rectangular planar magnetron with a moveable magnet assembly is known from U.S. Pat. No. 4,444,643, esp. FIGS. 10 and 11 thereof, in which the magnetic assembly is translated laterally and parallel to the major axis of the target. Further, DE-A-27 07 144 proposes a magnet assembly which is swept over a rectangular target along a linear path. As explained in U.S. Pat. No. 4,714,536, these known magnet and target assemblies do not provide a substrate with a satisfactorily uniform sputtered coat nor do they provide a satisfactorily uniform erosion of the target. U.S. Pat. No. 4,714,536 proposes that the magnet assembly is moved with a non-repetitive epicycloidal motion combined with a translational motion over the target, i.e. the magnet...

AI Technical Summary

Benefits of technology

Further, it is an object of the present invention to provide a simple drive mechanism for a planar magnetron and a simple and efficient cooling circuit.

It is a further object of the present invention to provide a magnet assembly which provides a high utilisation of the material of the target at least in a central region thereof.

Problems solved by technology

As explained in U.S. Pat. No. 4,714,536, these known magnet and target assemblies do not provide a substrate with a satisfactorily uniform sputtered coat nor do they provide a satisfactorily uniform erosion of the target.

The kidney bean shape does not produce an elongated plasma race-track and is not suitable for rectangular targets.

The drive mechanism for moving the magnet array is complex and large in size and requires separate guides for each of the motions.

This results in a complex universal joint in one of the drives.

The two drives from these motors take up a lot of space and both penetrate the vacuum chamber increasing the complexity of seals between the vacuum chamber and atmosphere and with the cooling circuit.

During sputtering, material from the target may be deposited onto the shields resulting in a layer of insulation which can break down locally causing arcing.

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